Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description goes further by disclosing the internal checks performed, the resulting $2.99 fee and arrival window, and explicitly scoping out capacity ('answered at booking') — meaningful context beyond the annotations, though permissions/rate limits are unaddressed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the decision question, then parameters, then return values, then the boundary against booking. No sentence is filler; the density is appropriate for the amount of behavior being conveyed.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only tool with no output schema and 0% schema coverage, the description does well by naming return values and the checks behind them. The remaining gaps are the parcel footprint implications and the store_id/pickup_address exclusivity, which an agent would need in order to call it correctly in all valid configurations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden for 6 parameters. It clarifies store_id (a registered store), dropoff_address, and the ready_at default of now, but says nothing about the parcel dimensions, the pickup_address alternative, or robomart_version — leaving three parameters undocumented anywhere.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with the exact question the tool answers ('Can this store deliver to this address at this ready time?') and enumerates the specific checks performed (store status, hours, coverage radius, network maximum, zone). It is instantly distinguishable from siblings like book_delivery or find_stores.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The closing sentence 'Capacity is answered at booking' implicitly routes the agent to book_delivery for capacity questions, which is a useful boundary. However there is no explicit statement of when to call this versus find_stores or list_stores, and the guidance to 'Send store_id... and dropoff_address' conflicts with the schema's anyOf allowing pickup_address instead.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.